U.S. Pat. No. 5,160,336 discloses a lithotripter having a handpiece which is adapted for holding a probe. The probe forms a waveguide which is adapted to transmit impact energy that is produced by a projectile. The projectile is pneumatically driven within a guide tube for periodically causing an impact force against the proximal end of the probe to thereby obtain shock waves at the distal end of the probe.
The probe is adapted for being inserted into an endoscope. Different sizes and diameters of the probe are provided for being used in an exchangeable manner under particular consideration of any specifically intended intracorporeal fragmentation of calculi. The holding means for the exchangeable probes as provided on the handpiece are generally designed as a screw cap having a seat for the proximal end of a probe whereby the proximal end of the probe has an enlarged head portion serving with its proximal face as an impact area for the projectile.
The screw cap further comprises a throughhole beyond which the distal end of the probe projects for its insertion into an endoscope. The screw cap has a male thread in engagement with a female thread on a cylindrical casing and sealed by means of an O-ring seal which is arranged on the screw cap. The screw cap thusly allows an easy exchange of the probes. The particular design of the holding means further allows a sterilization of the probes separate from the handpiece. Any sterilization of the handpiece necessitates, however, that after the removal of the screw cap the hollow of the casing in which the projectile is housed and which is then open to the air must first be closed by a separate sealing cap. By such closing also loss of the projectile during the sterilization of the handpiece will be prevented. The separate sealing cap finally also prevents any contamination of the projectile and of its guideway in the guidetube.